The key Cl− ligand for metal‐to‐ligand charge transfer in mononuclear terpyridine ruthenium(II) and binuclear ruthenium(II) tetrapyridylpyrazine complexes |
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Authors: | N. Yoshikawa S. Yamabe N. Kanehisa T. Inoue H. Takashima K. Tsukahara |
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Affiliation: | 1. +81 742 20 3395+81 742 20 3395;2. Department of Chemistry, Faculty of Science, Nara Women's University, , Nara, 630‐8506 Japan;3. Department of Chemistry, Nara University of Education, , Nara, 630‐8528 Japan;4. Division of Electrical, Electronic and Information Engineering, Osaka University, , Osaka, 565‐0871 Japan;5. Department of Applied Chemistry, Graduate School of Engineering, Osaka University, , Osaka, 565‐0871 Japan |
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Abstract: | Electronic structures of binuclear ruthenium complexes [Ru2(terpy)2(tppz)]4+ ( 1A ) and [Ru2Cl2(L)2(tppz)]2+ {L = bpy ( 2A ), phen ( 3A ), and dpphen ( 4A )} were studied by density functional theory calculations. Abbreviations of the ligands (Ls) are bpy = 2,2′‐bipyridine, phen = 1,10‐phenanthroline, dpphen = 4,7‐diphenyl‐1,10‐phenanthroline, terpy = 2,2′:6′,2″‐terpyridine, and tppz = tetrakis(2‐pyridyl)pyrazine. Their mononuclear reference complexes [Ru(terpy)2]2+ ( 1B ) and [RuClL(terpy)]+ {L = bpy ( 2B ), phen ( 3B ), and dpphen ( 4B )} were also examined. Geometries of these mononuclear and binuclear Ru(II) complexes were fully optimized. Their geometric parameters are in good agreement with the experimental data. The binuclear complexes were characterized by electrospray ionization mass spectrometry, UV–Vis spectroscopy, and cyclic voltammograms. Hexafluorophosphate salts of binuclear ruthenium complexes of 3A and 4A were newly prepared. The crystal structure of binuclear complex 1A (PF6)4 was also determined. Orbital interactions were analyzed to characterize the metal‐to‐ligand charge‐transfer (MLCT) states in these complexes. The Cl? ligand works to raise the orbital energy of the metal lone pair, which leads to the low MLCT state. Copyright © 2011 John Wiley & Sons, Ltd. |
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Keywords: | absorption properties DFT calculations ruthenium(II) complexes tetra‐2‐pyridylpyrazine |
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